The use of topical antimicrobial compositions to help treat, prevent or control diseases of man and other animals is an integral part of modern medicine. Topical antimicrobial compositions are also used to help prevent the spread of disease from animals to man, from man to animals and between animals. For example, antimicrobial compositions are used to disinfect meat carcasses in order to prevent food poisoning in humans. They are used on the teats of dairy animals such as cows and goats to help prevent mastitis and to help reduce the numbers of bacteria on the teat skin that could get into the milk during the milking process. Antimicrobial compositions may also be used in udder washes and both pre-milking and post-milking teat dips.
Because of the potential for contamination of milk by antimicrobial compositions used on cows teats, it is desired to use antimicrobial compositions that are generally recognized as safe, GRAS, as determined by the U.S. Food and Drug Administration in order to assure that any residues that may get into the milk from such uses are not toxic. Examples of antimicrobial compositions that are GRAS listed are both monoesters of edible fatty acids and polyhydric alcohols such as monolaurin and short to medium chained saturated fatty acids such as caprylic, capric, and lauric acids. In particular, the glycerol monoester of lauric acid (glycerol monolaurate or monolaurin) in combination with a chelating agent such as lactic acid is reported to be an effective antimicrobial system.
For example, U.S. Pat. No. 5,219,887 discloses the use of monolaurin with lactic acid as an antifungal, antibacterial system in a medicated shampoo. U.S. Pat. No. 5,208,257 discloses combinations of monolaurin, caprylic and capric acids with lactic acid as an effective antimicrobial system. U.S. Pat. No. 5,364,650 discloses the use of caprylic acid, capric acid, and a chelating agent without any monoester being present as a germicidal system useful for disinfecting animal carcasses to be used for human consumption. The concentrations of caprylic acid and capric acid in this system are kept very low (50-1500 ppm) so that they are soluble in water without the aid of other solvents or solubilizing surfactants. Kabara, J., Cosmetic and Drug Preservation, pp. 275-356, 1984, reports the use of monoglycerides, chelating agents, and medium chain fatty acids and combinations of these chemicals used as antimicrobial compositions, generally as preservatives.
U.S. patent application Ser. No. 08/121,283 filed Sep. 14, 1993 and International application No. PCT/U.S. 94/09370 filed Aug. 17, 1994 disclose the use of propylene glycol monoesters of edible fatty acids in combination with acids or chelating agents and GRAS anionic surfactants as a germicidal system useful for disinfecting meat carcasses to be used for human consumption.
Briefly, these exemplified reports are generally concerned with the use of monoglycerides as antimicrobial compositions and there is no detailed report other than U.S. application 08/121,283 and the related International application No. PCT/U.S. 94/09370, of the use of propylene glycol monoesters as antimicrobial compositions.